1. Field of the Invention
The present invention relates to a spacer structure, and more particularly, to a spacer structure which is disposed in a display panel for enhancing the compression strength of the display panel.
2. Description of the Prior Art
A liquid crystal display (LCD) panel is mainly composed of a thin film transistor substrate (TFT substrate), a color filter substrate (CF substrate), and liquid crystal molecules filled between the TFT substrate and the CF substrate. In order to provide stable display quality, spacers are installed between the TFT substrate and the CF substrate so that the cell gap between the TFT substrate and the CF substrate can be maintained.
FIG. 1 is a schematic diagram illustrating conventional spacers. As shown in FIG. 1, the conventional spacers 10 are disposed between a TFT substrate 12 and a CF substrate 14 of a display panel, where an overcoat layer 16 is disposed between each of the spacers 10 and the CF substrate 14, and a spacer pad 18 is disposed between each of the spacers 10 and the TFT substrate 12.
As shown in FIG. 1, the conventional spacers 10 have the same height, the spacer pads 18 have the same thickness, and the overcoat layers 16 have the same thickness. Accordingly, the display panel has a uniform cell gap by virtue of the spacers 10, the spacer pads 18 and the overcoat layers 16 with the same height or thickness under normal condition. The display panel, however, may be inevitably compressed by external forces when used. In such a case, breakage or permanent deformation may occur to the substrates easily due to the insufficient buffer effect against external compression of the conventional spacers 10.
In order to improve the tolerance against external compression, another spacer design has been proposed. FIG. 2 is a schematic diagram illustrating other conventional spacers. As shown in FIG. 2, the conventional spacers 10 have the same height, but the spacer pads 18 are installed only in some regions (e.g. main regions), while no spacer pads are installed in other regions (e.g. subsidiary regions). In other words, the spacer pads 18 are arranged in a manner such that the spacers 10 and the spacer pads 18 are in contact to each other in the main regions, while a gap is formed between each of the spacers 10 and the TFT substrate 12 in the sub regions. Therefore, external compression forces may be buffered. The TFT substrate 12 and the CF substrate 14, however, are fabricated by different manufacturers, which may affect the integrity of the display panel. Also, the alignment error of the TFT substrate 12 and the CF substrate 14 would influence the relative position between the spacer pad 18 and the spacer 10, which would deteriorate the buffer effect with respect to external compression forces.